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Uninterruptable?
- Thread starter docherf
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- Tesla Energy
I have had my Powerwall for over 2 months. I have tested the auto switchover when the grid fails (simulated it by flipping the disconnect switch). There is about a 10-15 second period before the Powerwall (and solar if the sun is up) kicks in and powers the circuits in my "critical loads" subpanel.
So not the same as a real UPS, but close enough for my purposes. I do not have anything in my house that requires a UPS.
deonb
Active Member
Ugh. (As I click the Amazon order for my 4th UPS).
I wish UPS would be a bigger priority for Tesla.
A Model S is a better power source than almost anything you can buy - I just want about 20 kWh a year of UPS backup - nothing a Model S can't handle over its lifetime.
I just need that tiny bit. Power interruptions lasting for more than an hour is rare. But even a 5 second power interruption will ruin a 6 hour 3D print.
Perfectly willing to install a $3000 HPWC/Transfer Switch combo device to make this happen. Come on Tesla!
Your use case is uncommon for a residence. You can't expect Tesla to address rare use cases for a mass market product, especially when it is easy to address the use case with an off-the-shelf UPS.
deonb
Active Member
JPP
Active Member
I have always kept a bunch of small UPS on key devices (computers, modems, phone switch, alarm system) to cover the occasional glitches and outages. I did this when I lived in a house with a 25kw natural gas fired standby generator, as it took about 30-60 seconds to spin up, stabilize and pick up the loads. I would assume that a 3D printer (like a laser printer) pulls quite a bit of current, and using a 'conventional' UPS would not be an adequate bridge until the Powerwall kicked in.
Brovane
Member
I think you are asking for one thing but actually thinking of another.
My experience in dealing with UPS is from a DataCenter environment. A standard UPS sits between the system it is protecting and the grid. This means the protected system is running off "battery power" and the UPS is continually charged from a External source (either generator or commercial power. This makes it so the protected system is completely protected from surges, sags or outages as long as the batteries have enough power. So in theory if a PW could feed certain circuits continuously (like a circuit feeding a 3D printer) then that circuit would still be up even during a power loss because the PW is running the circuit. In theory you are basically making those circuits off-grid and a external power source feeds the PW to keep the batteries charged. Since the powerwall can be used in a off-grid scenario then I don't see much issue with accommodating this type of programming.
When you mention cutover time, what you are really saying is SPS (That is a Stand-by Power System). In a SPS setup the protected equipment runs on commercial power, however that commercial power is feed and condition through the SPS. The SPS batteries are allowed to float with a set charge (This makes the batteries last longer) and the SPS monitors the electrical feed into the unit and in the even of a power issue the SPS will cutover in milli-seconds to keep the units up on battery power. You are probably never going to see this capability with a PW unit.
Part of the reason I got battery backup with my solar was to jettison the 3 in-house UPS devices that (a) were generating heat indoors and (b) spaghetti monsters for devices to meet at.
I don't think the desire to simplify via whole-home UPS (well, selected circuits...) is that uncommon. Hearing this about Powerwall makes me reconsider Tesla's offering as an upgrade when my batteries are due for replacement.
I agree, and do not recommend that anyone buy a Powerwall thinking it will provide the same capability as a true UPS, if that is a requirement for them. The Powerwall does not provide "uninterruptible" power.
Just having an off grid configuration does not mean you do not need UPS if that is important. We are off grid, everything runs from the batteries through the inverter. We have had several instances of losing power for different reasons, the first being a bad cable installation. Took me a bit to figure it out, after all, this was a professionally installed system. Another time a board went bad in the primary inverter, another time a breaker crapped out. While we don't have nearly the outages our grid tied neighbors have, they do happen, usually short lived, just different reasons.
Brovane
Member
You can have outages because of a UPS issue. I have seen plenty of times a small UPS in some out of the way IT closet bring down critical equipment because the batteries failed and then that brought down the equipment. That is why good UPS's will have a bypass to commercial power in the event of battery failure. For data-centers if you want true HA you will have completely redundant A-B power systems with separate paths.
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